Axial piston pumps



Feb. 7, 1956 H. POULOS AXIAL PISTON PUMPS 3 Sheets-Sheet 1 Filed Feb. 20, 1953 INVENTOR.

IIIIII 5 Sheets-Sheet 2 Filed Feb. 20, 1953 & A

E-II 22 FIG-.3

INVENTOR. HARRY POULOS Feb. 7, 1956 Filed Feb. 20, 1953 H. POULOS 2,733,666

AXIAL PISTON PUMP-S 3 Shets-Sheet 3 FIG. 4

INVENTOR.

HARRY POULOS AXIAL PISTON PUMPS Harry Poulos, Columbus, Ohio, assignor to The Denison Engineering Company, Columbus, Ohio, a corporation of Ohio Application February 20, 1953, Serial No. 337,904.

Claims. (Cl. 103-162) Unitfid States atent 0 rotation of the cylinder barrel had to be stopped before the valve plate re-engaged with the cylinder barrel and normal operation was resumed. One object of this invention is to provide a motor or pump capable of maintaining pressure without'interrupting the operation of the device.

An object of this invention also is to provide a liquid pump or motor, having a sealing ring adjacent to the valve plate whereby fluid pressure will be directed to an area at the opposite end of the cylinder barrel when separated from the valve plate to force the cylinder barrel into engagement with the valve plate by fluid pressure acting upon the end area opposite the valve end thereby restoring normal operation of the device.

Another object of this invention is to provide an axial piston pump or motor having a rotating cylinder barrel with valve and cam plates at opposite ends thereof, a sealing ring which surrounds the valve and is spring loaded against one end ofthe cylinder barrel to keep fluid from draining directly to tank, when the cylinder barrel separates from the valve plate. The sealing ring will apply fluid under pressure to the cylinder barrel to re-engage the same with the valve plate whereby normal operation of the device will be resumed.

, Afurther object of this invention is to provide an axial piston pump or motor having a casing with a rotating cylinder barrel disposed therein with valve and cam plates at opposite ends thereof having a sealing ring at the valve at the cam end of the casing, and a restricted orifice to build up fluid pressure before the fluid is directed to the drain. The fluid acting on the cam end of the cylinder barrel will cause the cylinder barrel to re-engage itself with the valve plate after it has been disengaged therefrom, making it unnecessary to interrupt the operation of the device.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Fig. 1 is part in elevation and part a vertical longitudinal sectional view taken through a pump or motor formed in accordance with the present invention.

Fig. 2 is an enlarged vertical longitudinal sectional view of the pump or motor showing the sealing ring suspension and the cylinder barrel and valve plate in disengagement.

Fig. 3 is a vertical longitudinal sectional view taken through a pump or motor showing a sealing ring, restricted annular orifice, drain, and the cylinder barrel and valveplate in disengagement.

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Fig. 4 is a partial longitudinal sectional view taken through the pump shown in Fig. 1 and illustrating the relation of the inlet and outlet port, the valve plate and the sealing ring provided in accordance with the invention.

Referring more particularly to the drawings, the numeral 20 designates the pump or motor to which the invention has been adapted. This pump or motor has a casing 21 including-a drain 53, a body 22, a head 23, and an end cap 24 secured together to make a unit having an internal chamber 25. This chamber receives a cylinder barrel 26, a valve 27, a cam plate 28, and a sealing ring 29, the cam plate being disposed at one end of the cylinder barrel, the valve plate and the sealing ring being arranged at the other end between the cylinder barrel 26 and the head 23. The opposed ends of the head and cylinder barrel have bearing surfaces 30 and 31 for engagement with opposite sides of the valve plate 27. The cylinder barrel is disposed for rotating movement in casing 21 and is supported by roller bearing 32. The inner bearing race 33 is formed on the cylinder barrel and the outer bearing race 34 makes up part of the casing 21 of the pump or motor.

The head has a central opening 35 to receive a shaft 36 which is journaled in bearings 37 mounted in the head. The inner end of the shaft 36 has a splined connection 38 with the cylinder barrel 26 so that, when the shaft is revolved, similar movement will be imparted to the cylinder barrel. Cylinder barrel 26 is formed with a plurality of axially extending chambers 39 for slidable reception of piston elements 40, the reciprocation of which in the chambers 39 serves to govern the flow of fluid into and out of chambers 39 through openings 40A in the end of the cylinder barrel and arcuate ports 40B and 400 provided in the valve plate 27. These ports are in constant communication with chambers 40D and 40E in the head 23, which chambers communicatewith inlet and outlet conduits, not shown.

7 Each piston 40 is provided with a spherical head 41 to which is universally connected a bearing shoe 42, the latter members being in sliding engagement with the surface 43 of the cam member 28. The engagement between the shoe and the cam surface 43 is maintained by a retainer plate 44 which surrounds the'shoes 42 and engages shoulders 45 formed thereon, the plate being. urged toward the cam by ball 46 and plunger 47 movably positioned in a sleeve 48 which is disposed in a socket 49 formed in the inner end of the shaft 36. Coil spring 50 is positioned between a Wall of plunger 47 and a flange 51 at the inner end of sleeve 48. This spring tends to force the plunger 47 out of the sleeve 48 thus causing the former to exert a yieldable force on the plate 44. The outer end of the sleeve 48 has an annular flange 52 formed thereon, which flange engages the outer end of the cylinder barrel 26 and tends to move the same toward the valve plate 27.

The valve plate 27 is held in place by pins .61 which project from the head 23. Spring 50 thus serves two functions, first, that of urging the bearing shoes 42 in engagement with the cam surface and, second, the urging of the cylinder barrel 26 toward sliding engagementwith valve plate 27.

From an inspection of Figs. 1 and 3, it will be observed that surface 43 of the cam plate 28, with which the bearing shoes 42 are engaged, isinclined with respect to the axis of rotation of the cylinder barrel. Due to the inclination of the surface, the pistons 40 will be reciprocated "from the valve plate as shown in Figs. 2 and 3. Dis- "en'g'a'g'ement of the cylinder barrel from the valve plate be explained as the formation of a wedgeof fluid under pressure between the cylinder barrel and valve plate which increases in size until the cylinder barrel .is sep arated from the valve plate andjridi'ng over 'a heavy film of fluid. Prior to this invention, the fluid escapin'gbe tween the cylinder barrel and valve plate was directed into the casing'25 and out to drain 53 causing the piunp or motor to lose direct communication with the pressure port and become ineffective. According to this invention, a sealing ring 29 is inserted between the head 23 and cylinder barrel 26 and fluid escaping from the pressure port 40A is directed; as shown by arrows in Fig. 3, through passages '54 to central opening 35,'through groove 55 in the splined shaft 36 and milled slots 56 on the annular flange 52 and into the cam end of the casing. Fluid pressure entering the cam end of the'casing is held under pressure by an annular orifice 58 between such end of the casing and drain 53. The area of the cylinder barrel at the cam end is greater than that at the valve end of the cylinder barrel permitting fluid to exert more force at the cam end of the cylinder barrel and thus urge the cylinder barrel into engagement with the valve plate. The sealing ring 29 has an outside diameter slightly'smaller than the bore of body 22 adjacent the head 23 and has drilled holes 62 which receive coil springs 59. These coil springs are held in place by pins 66 which project from the head 23 so the sealing ring is constantly spring loaded against the cylinder barrel forming a constant seal between the valve end of the cylinder barrel and chamber 25.

One of the advantageous results of the present construction is an increase in efliciency over that secured in previous devices of this character. The increased efliciency is due to'resumption of normal operation of the pump or motor without having to stop the operation of the pump or motor to re-engag'e the cylinder barrel and valve plate whenever the cylinder barrel would separate from the valve plate. Previously, the only known method of engaging the cylinder barrel with the valve plate was to completely stop the operation of the pump or motor and rely on the coil spring 50 to urge the cylinder barrel into sliding engagement with the valve plate. This previous method of stopping the operation of the pump or motor does not assure that the cylinder barrel and valve plate will remain in engagement immediately after the pump or motor is put in operation again. In the present construction, continual operation of the pump or motor is assured.

While the form of embodiment of the present invention as'herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all

coming Within the scope of the claims which follow.

I claim:

1. A fluid energy translating device comprising a casing having a chamber and a drain extending therefrom; a head with inlet and outlet ports at one end of said chamber; a valve plate disposed in engagement with said head; a cylinder barrel disposed for rotary movement within said chamber and normally in sliding engagement with said valve plate; pistons disposed for reciprocatory movement within said cylinder barrel; a cam means at the op posite end of said chamber from said head for controlling the movementof said pistons; a seal means surrounding said valve plate and yieldably engaging the valve end of said cylinder barrel; a passage to direct fluid from the re- -gion enclosed by said seal means to the cam end of said chamber; and a restricted orifice between said drain and the cam end of said chamber to resistfluid flow from the 'camend of said chamberto said drain and create a back pressure, said back pressure being applied to the cam end of-said cylinder barrel to urge-said cylinder barrel toward said valve plate. e

2. A fluid energy translating device comprising a cas-- ing forming a chamber and having a member with inlet and outlet ports; a valve means engaging said member; a drain means extending from said casing; a rotating cylinder barrel normally in sliding engagement with said valve; pistons reciprocating Within said cylinder barrel; a cam means for controlling movement of said pistons; a seal means at said valve end of said cylinder barrel to prevent direct communication between the valve end of said chamber and said drain; a passage extending from said valve end to the opposite end of said cylinder barrel to conduct fluid escaping past said valve means to the opposite end of chamber; and a restricted orifice between the latter end of said chamber and said drain, said orifice restricting fluid flow from said latter end of said chamber and creating a pressure drop, the higher pressure of said pressure drop being applied to said cylinder'barrel to urge the same into engagement with said valve means.

3. A fluid pressuretranslating device comprising a casing having a chamber and a drain extending therefrom;

ahead with inlet and outlet ports at one end of said chamber; a valve disk disposed in engagement with said head for communication with said inlet and outletports; a cylinder barrel having one end normally engaged with said valve disk; a sealing ring in sliding engagement with said cylinder barrel, said sealing ring serving to prevent fluid escaping past said valve disk from flowing directly to said drain; a restricted orifice means to resistfluid flow to said drain and create back pressure in said casing, said back pressure being applied to the end of said cylinder barrel opposite said valve disk to urge said barrel into engagement with said valve disk; piston means disposed for movement in said cylinder barrel; and a cam plate at one end of said cylinder barrel to control the movement of said pistons.

4. A fluid pressure energy translating device comprising a casing forming a chamber with a valve surface at one end, said valve surface having inlet and outlet ports; a cylinder barrel supported for rotation in said chamber With one end in slidable engagement with said valve surface; piston means disposed for reciprocation in said cylinder barrel; means for imparting reciprocatory movement to said pistons; means forming a drain from said chamber intermediate the ends of said cylinder barrel; sealing means between said casing and the end of said cylinder barrel in engagement with said valve surface to prevent fluid escaping between said valve surface and said cylinder barrel from flowing directly to said drain; means forming a passage to conduct fluid from the valve surface end of said chamber to the opposite-end; and means for resisting fluid flow from the latter end of said chamber to said drain to create back pressure, said back pressure tending to urge said cylinder barrel toward said valve surface.

5. A fluid pressure energy translating device comprising a casing forming a chamber with a valve surface having inlet and outlet ports; a cylinder barrel disposed with a first surface in rotary sliding engagement with said valve surface; piston means disposed for reciprocation in said cylinder barrel; means in said casing for controlling the reciprocatory movement of said piston means; means forming a drain for said chamber, said cylinder barrel having a second surface facing said drain and a third surface opposed to said first and second surfaces; seal means between the first surface of said cylinder barrel and said casing to prevent the flow of fluid escaping between said valve surface and cylinder barrel directly to said drain; passage means extending from the space in said chamber adjacent said valve surface to a space in said chamberadjacentthe third surface and thence over said second surface to said drain; and flow restricting means in said passage means between the space adjacent said third surface and said drain to create a back pressure, the force of such back pressure on said third surface 7 tending to urge said cylinder barrel toward said valve surface.

References Cited in the file of this patent UNITED STATES PATENTS 

